<template>
  <div>
    <div class="goods">
      <div class="menu-wrapper" ref="menuWrapper">
        <ul>
           <!-- current -->
          <li class="menu-item" v-for="(good,index) in goods" :key="index" :class="{current:currentIndex===index}" @click="clickMenuItem(index)">
            <span class="text bottom-border-1px">
              <img
                :src="good.icon" v-if="good.icon"
                class="icon"
              />
              {{good.name}}
            </span>
          </li>
        </ul>
      </div>
      <div class="foods-wrapper" ref="foodsWrapper">
        <ul ref="foodsUl">
          <li class="food-list-hook" v-for="(good,index) in goods" :key="index">
            <h1 class="title">{{good.name}}</h1>
            <ul>
              <li class="food-item bottom-border-1px" v-for="(food, index) in good.foods" :key="index" @click="showFood(food)">
                <div class="icon">
                  <img
                    v-lazy="food.icon"
                    width="57"
                    height="57"
                  />
                </div>
                <div class="content">
                  <h2 class="name">{{food.name}}</h2>
                  <p class="desc">{{food.description}}</p>
                  <div class="extra">
                     <span class="count">月售{{food.sellCount}}份</span>
                     <span>好评率{{food.rating}}%</span>
                  </div>
                  <div class="price">
                     <span class="now">￥{{food.price}}</span>
                     <span class="old" v-if="food.oldPrice">{{food.oldPrice}}</span>
                  </div>
                  <div class="cartcontrol-wrapper">
                     <CartControl :food="food"/>
                  </div>
               </div>
              </li>
            </ul>
          </li>
        </ul>
      </div>
      <!-- 购物车结算组件 -->
      <ShopCart/>
    </div>
    <!-- 食物组件 -->
    <Food :food="food" ref="food"/>
  </div>
</template>

<script>
import {mapState} from 'vuex'
import BScroll from 'better-scroll'
import CartControl from '../../../components/CartControl/CartControl'
import Food from '../../../components/Food/Food'
import ShopCart from '../../../components/ShopCart/ShopCart'
export default {
  mounted(){
     this.$store.dispatch("getShopGoods",()=>{ //函数是数据更新之后执行
        this.$nextTick(()=>{ //列表数据更新显示之后执行
         this._initScroll();
         this._initTops();
        })
     });
  }, 
  name: "",
  data() {
    return {
       scrollY:0,//右侧活动的y轴坐标(滑动过程实时变化)
       tops:[],//所有右侧分类li的top值组成的数组(列表第一次显示后就不再变化)
       food:{},//需要显示的food
    };
  },
  methods: {
     //初始化滚动条
     _initScroll(){
         //列表显示之后创建
        this.bs_menu = new BScroll('.menu-wrapper', {
            scrollY: true,
            click: true
         });
        this.bs_foods = new BScroll('.foods-wrapper', {
            scrollY: true,
            click: true,
            probeType:2 //因为惯性的滑动不会触发
         });
         //给右侧列表绑定scroll监听
         this.bs_foods.on("scroll",({x,y})=>{
            this.scrollY = Math.abs(y); //  scrollY: 右侧滑动的Y轴坐标 (滑动过程时实时变化)
         });
         //给右侧列表绑定scroll监听
         this.bs_foods.on("scrollEnd",({x,y})=>{
            this.scrollY = Math.abs(y); //  scrollY: 右侧滑动的Y轴坐标 (滑动过程时实时变化)
            console.log("scrollEnd",y);
         });
     },
      //初始化tops
     _initTops(){
        //1.初始化tops
        const tops = [];
        let top = 0;
        tops.push(top);
        //2.收集
        //找到所有的li
        const lis = this.$refs.foodsUl.getElementsByClassName("food-list-hook");
        Array.prototype.slice.call(lis).forEach(li => {
           top += li.clientHeight;
           tops.push(top);
        });
        //3.更新数据
        this.tops = tops;
     },
     clickMenuItem(index){
      //console.log(index)
      //使右侧列表滑动到对应的位置
      //得到目标位置的scrollY
        const y = this.tops[index];
        //立即更新scrollY(让点击的分类xiang成为当前分类)
        this.scrollY = y;
        //平滑滚动右侧列表
        this.bs_foods.scrollTo(0,-y,500);
     },
     //显示点击的food
     showFood(food){
        //设置food
        this.food = food;
        //显示food组件(调用子组件的方法)
        this.$refs.food.toggleShow();
     }
  },
  computed:{
     ...mapState(['goods']),
     currentIndex(){ //初始和相关数据发生了变化
        //先得到条件数据
        const {scrollY,tops} = this;
        //根据条件计算产生一个结果
        let index = tops.findIndex((top,index)=>scrollY>=top && scrollY<tops[index+1]);
        //返回结果
        return index;
     }
  },
  components:{
     CartControl,
     Food,
     ShopCart
  }
};
</script>
<style  lang='stylus' rel='stylesheet/stylus'>
@import "../../../common/stylus/mixins.styl"
  .goods
    display: flex
    position: absolute
    top: 195px
    bottom: 46px
    width: 100%
    background: #fff;
    overflow: hidden
    .menu-wrapper
      flex: 0 0 80px
      width: 80px
      background: #f3f5f7
      .menu-item
        display: table
        height: 54px
        width: 56px
        padding: 0 12px
        line-height: 14px
        &.current
          position: relative
          z-index: 10
          margin-top: -1px
          background: #fff
          color: $green
          font-weight: 700
          .text
            border-none()
        .icon
          display: inline-block
          vertical-align: top
          width: 12px
          height: 12px
          margin-right: 2px
          background-size: 12px 12px
          background-repeat: no-repeat
        .text
          display: table-cell
          width: 56px
          vertical-align: middle
          bottom-border-1px(rgba(7, 17, 27, 0.1))
          font-size: 12px
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left: 2px solid #d9dde1
        font-size: 12px
        color: rgb(147, 153, 159)
        background: #f3f5f7
      .food-item
        display: flex
        margin: 18px
        padding-bottom: 18px
        bottom-border-1px(rgba(7, 17, 27, 0.1))
        &:last-child
          border-none()
          margin-bottom: 0
        .icon
          flex: 0 0 57px
          margin-right: 10px
        .content
          flex: 1
          .name
            margin: 2px 0 8px 0
            height: 14px
            line-height: 14px
            font-size: 14px
            color: rgb(7, 17, 27)
          .desc, .extra
            line-height: 10px
            font-size: 10px
            color: rgb(147, 153, 159)
          .desc
            line-height: 12px
            margin-bottom: 8px
          .extra
            .count
              margin-right: 12px
          .price
            font-weight: 700
            line-height: 24px
            .now
              margin-right: 8px
              font-size: 14px
              color: rgb(240, 20, 20)
            .old
              text-decoration: line-through
              font-size: 10px
              color: rgb(147, 153, 159)
          .cartcontrol-wrapper
            position: absolute
            right: 0
            bottom: 12px
</style>